In order to prevent intruders, most commercial buildings, office buildings, industry structures, and residential houses have installed security or burglary alarm systems. Normally, during the business hours or when the owner is still staying inside the structure, the alarm system is disarmed. After the business hours or when there is nobody inside the structure, the owner will set the alarm system in armed condition before he or she leaves.
Pursuant to the current National Life Safety/Fire codes, all the emergence entrances or exits of a commercial structure or public area such as warehouses or stairways must remain unlocked 24 hours a day for safety purposes. Therefore, some buildings such as warehouses or factories must keep their entrances and exits unlock even when their alarm systems are disarmed during the business hours. It is unreasonable to have security guards monitoring all the unlocked entrances or exits during the business hours. Think about that if your home door must remain unlock when you are at home, it is absolutely not a secure matter. To those huge size warehouses, valuable goods are stored therein. Also, to those business buildings, valuable properties or expensive equipements are everywhere. However, all kinds of intruder are free to enter and exit such unlocked entrances or exits anytime. Therefore, how to laborlessly monitor such unlocked entrances or exits becomes the first topic to those buildings and structures.
It seems to be the only solution to reduce the necessary number of security guards being hired by installing at every unlocked entrances and exits with expensive video camera, additional security devices and individual systems such as door exit alarms or door push bar alarm devices. However, to monitor numbers of monitoring screens simultaneously in the security room without any mistake is impossible. An intruder may easily enter the structure even when the security guard moves his or her eyes away from the corresponding monitoring screen or the passive VCR recording system for seconds. Moreover, if the conventional battery operated individual push bar alarm device is installed at the entrance/exit door, the user must test the push bar alarm device periodically to ensure whether it is functioning normally. In conclusion, the conventional security method is expensive but inefficient.
Also, pursuant to the National Building Codes, if there is a swimming pool within a housing area, for children safety, all passages and exits that can reach the swimming pool must provide alert system to generate alert signals when that exit door is opened every time. The main objective of this regulation is to prevent the minors or seniors in a family from being accidentally fallen into the swimming pool and drown. However, although every exit door has installed a door sensor if an alarm system is installed to protect the housing area, the alarm system is normally disarmed when the residents are at home. In other words, all the door sensors will not function when there is any resident at home. Besides, an armed alarm system will only provide continuous alert siren even when the owner himself or herself open the door.
Accordingly, the swimming pool owner must install expensive additional door alarm systems and/or individual warning or guarding systems to all the exit doors. Independent buzzer is also required to be install at home to provide alarm for such as 30 seconds when any one of the additional door sensors is triggered so as to warn the house owner that the exit door is opened and a minor may have the chance to reach the swimming pool. Although it sounds like a stupid thing to install two door alarm systems at one door, it is the only solution currently.